DE 197 09 842 C1 discloses an electro-optical coupling assembly with a laser diode arrangement in which a plurality of vertically emitting VCSEL laser diodes are arranged in an array. The laser diodes are assigned optical waveguides which are arranged in one plane and whose coupling-side end faces effect beam deflection of the light emitted by the laser diodes into the optical waveguides.
It is known, in the case of such laser diode arrangements, to provide one or more monitor diodes via which the laser diode arrangement is monitored and controlled.
A corresponding construction known in the prior art is shown diagrammatically in FIG. 7. Accordingly, a laser diode array 101, comprising sixteen VCSEL diodes 102 in the exemplary embodiment illustrated, is arranged on a submount 100. Twelve of these laser diodes 102 serve for data communication and they are accordingly assigned in each case a diagrammatically illustrated optical waveguide 103. The two laser diodes 104, 105 situated at the edge of the array 101 are respectively assigned a monitor diode 111, 112 which is composed of gallium arsenide and whose optically active area is positioned directly above the respective outermost laser diode 104, 105 and faces the latter.
As an alternative, it would also be possible to provide the optically active area of the photodiode at the side remote from the laser diodes 104, 105, that is to say at the top. However, a deflection optical arrangement would then be necessary in order to direct the laser beam onto the optically active area of the monitor diode.
The monitor diode 111, 112 is respectively formed in a carrier 113, 114, which is fixed to a submount 115, 116 serving as spacer element or spacer. The submount is a ceramic carrier.
The monitor diodes 111, 112 and also the laser diodes 102, 104, 105 are contact-connected via bonding wires 117, which are connected via metallizations 118 and further bonding wires 119 to contacts of a diagrammatically illustrated control and driver circuit 120.
Submount 115, 116 and monitor diode 111, 112 are positioned at a right angle with respect to one another, so that, on the one hand, the monitor diode projects with its optically active area over the spacer and, on the other hand, there is space on the spacer for contact pads for connecting the bonding wires 119.
The two monitor diodes 111, 112 are usually used in such a way that the optical output power of the laser diodes 102 is regulated with the aid of one monitor diode 111, while the other laser diode 112 effects a safety shutdown for the case where the laser power exceeds a predetermined limit value. Such instances of regulation are known per se.
For the electrical and mechanical connection of submount 115, 116 and monitor diode 111, 112, it is known to connect the two chips by means of flip-chip mounting. Flip-chip mounting aligns the two singulated components by turning one chip and subsequently positioning it on the other chip located in a workpiece carrier. In this method, the fact that one component has to be positioned in a workpiece carrier after singulation is disadvantageous. The method is time-consuming and the small size of the singulated chips (approximately 2 mm×2 mm) is difficult to handle. Moreover, the method is cost-intensive which it involves a single-chip process, i.e. complicated and expensive individual productions.